Need a great listing platform something like real estate

[DropWizard.com]

I'm looking for recommendations on a platform that is reasonably inexpensive.

Great graphics and control of them EASILY. There are too many programs where you have to stop and figure out what they're talking about (huge learning curve)
Something like a real estate site but not the same
Something like a business listing site but not the same
Something like a classified site but not the same

Not an auction site.

SEO friendly
Something that can grow with time and not need to be replaced by under 50k users
Shopping cart friendly
Pictures yes
Chat no
Easily sub classified into relevant areas
Advertiser friendly
Admin friendly
Listing area can have extra lines (information additions)
Probably PHP based as I can't write php but I can usually modify lines of code to get what I want
Obviously source files available
Listings can be set for various periods

The closest to what I'm looking for would most likely be the business or car listing site in look and functionality with the user able to set their own listings for duration and options.

 

[INFORG]

Check out the wordpress themes from premiumpress.com they have some pretty flexible/functional stuff that you might be able to easily get to what you are looking for.

 

[DropWizard.com]

I've built a lot of wordpress sites and have seen these before. I don't think Wordpress will have the functionality that I'm looking for. I'm really concerned about the # of users and the number of sub categories generated. The Nav in wordpress will get quite "busy" Also the load speed although caching will help. Worpress also runs some cron functions that slow servers once they get past the 400-500 page size.

I've had 3-4 large sites shut down without notice by the hosting once they started affecting server load.

(PS I anticipate creating something close to 1000 categories and subs almost right away.)

That said I'm looking at the wp classified plugin right now